Converting the Word Problem into a Linear Inequality

Oct 13, 2025 by miodeya.com 43 views

Understanding Linear Inequalities

Linear inequalities are mathematical expressions that compare two values using the greater than or less than symbols. They are often used to represent real-world situations where a certain condition must be met. In this article, we will explore how to convert linear inequalities into word problems, using the example of a roller coaster ride.

Converting the Word Problem into a Linear Inequality

Let's start with the word problem: "You must be at least 13 to ride a roller coaster." This can be translated into a linear inequality as follows:

Let z be the age of the person.
The condition is that the person must be at least 13 years old.
This can be represented as z ≥ 13.

Converting the Linear Inequality into a Word Problem

Now, let's convert the linear inequality $-4z + 6 > 10$ into a word problem. To do this, we need to understand the meaning of the inequality.

The inequality is in the form of $az + b > c$ , where a, b, and c are constants.
The coefficient of z is -4, which means that the value of z is being multiplied by -4.
The constant term is 6, which is being added to the product of -4z.
The inequality is greater than 10, which means that the value of the expression is greater than 10.

Breaking Down the Linear Inequality

To convert the linear inequality into a word problem, we need to break it down into its components.

The coefficient of z is -4, which means that the value of z is being multiplied by -4. This can be represented as "4 times the value of z".
The constant term is 6, which is being added to the product of -4z. This can be represented as "6 more than 4 times the value of z".
The inequality is greater than 10, which means that the value of the expression is greater than 10. This can be represented as "greater than 10".

Creating a Word Problem

Now that we have broken down the linear inequality into its components, we can create a word problem.

Example 1: Tom has 4 times as many pencils as his friend Alex. If Alex has 6 more pencils than Tom, and Tom has more than 10 pencils, how many pencils does Tom have?

Solution: Let z be the number of pencils that Tom has. Then, the inequality can be written as:

-4z + 6 > 10

This can be rewritten as:

4z < 4

z < 1

Since z represents the number of pencils that Tom has, the solution is that Tom has less than 1 pencil. However, this is not a realistic solution, as Tom cannot have a fraction of a pencil.

Example 2: A bookshelf has 4 times as many books as a nearby bookcase. If the bookcase has 6 more books than the bookshelf, and the bookshelf has more than 10 books, how many books does the bookshelf have?

Solution: Let z be the number of books that the bookshelf has. Then, the inequality can be written as:

-4z + 6 > 10

This can be rewritten as:

4z < 4

z < 1

Since z represents the number of books that the bookshelf has, the solution is that the bookshelf has less than 1 book. However, this is not a realistic solution, as a bookshelf cannot have a fraction of a book.

Example 3: A company has 4 times as many employees as a nearby company. If the nearby company has 6 more employees than the company, and the company has more than 10 employees, how many employees does the company have?

Solution: Let z be the number of employees that the company has. Then, the inequality can be written as:

-4z + 6 > 10

This can be rewritten as:

4z < 4

z < 1

Since z represents the number of employees that the company has, the solution is that the company has less than 1 employee. However, this is not a realistic solution, as a company cannot have a fraction of an employee.

Conclusion

Converting linear inequalities into word problems can be a challenging task, but it requires a deep understanding of the meaning of the inequality. By breaking down the inequality into its components and creating a word problem, we can make the inequality more accessible and easier to understand. In this article, we have explored how to convert the linear inequality $-4z + 6 > 10$ into a word problem, using the example of a roller coaster ride. We have also created three word problems to illustrate the concept.

References

[1] Khan Academy. (n.d.). Linear Inequalities. Retrieved from https://www.khanacademy.org/math/algebra/x2f-linear-inequalities/x2f-linear-inequalities/x2f-linear-inequalities
[2] Math Open Reference. (n.d.). Linear Inequalities. Retrieved from https://www.mathopenref.com/linearinequalities.html
[3] Wolfram MathWorld. (n.d.). Linear Inequalities. Retrieved from https://mathworld.wolfram.com/LinearInequalities.html

Word Problem Examples

A person has 4 times as many dollars as their friend. If their friend has 6 more dollars than they do, and they have more than 10 dollars, how many dollars do they have?
A company has 4 times as many employees as a nearby company. If the nearby company has 6 more employees than the company, and the company has more than 10 employees, how many employees does the company have?
A bookshelf has 4 times as many books as a nearby bookcase. If the bookcase has 6 more books than the bookshelf, and the bookshelf has more than 10 books, how many books does the bookshelf have?

Solutions

Let z be the number of dollars that the person has. Then, the inequality can be written as: -4z + 6 > 10 This can be rewritten as: 4z < 4 z < 1 Since z represents the number of dollars that the person has, the solution is that the person has less than 1 dollar. However, this is not a realistic solution, as a person cannot have a fraction of a dollar.
Let z be the number of employees that the company has. Then, the inequality can be written as: -4z + 6 > 10 This can be rewritten as: 4z < 4 z < 1 Since z represents the number of employees that the company has, the solution is that the company has less than 1 employee. However, this is not a realistic solution, as a company cannot have a fraction of an employee.
Let z be the number of books that the bookshelf has. Then, the inequality can be written as: -4z + 6 > 10 This can be rewritten as: 4z < 4 z < 1 Since z represents the number of books that the bookshelf has, the solution is that the bookshelf has less than 1 book. However, this is not a realistic solution, as a bookshelf cannot have a fraction of a book.
Q&A: Converting Linear Inequalities into Word Problems =====================================================

Frequently Asked Questions

Q: What is a linear inequality? A: A linear inequality is a mathematical expression that compares two values using the greater than or less than symbols. It is often used to represent real-world situations where a certain condition must be met.

Q: How do I convert a linear inequality into a word problem? A: To convert a linear inequality into a word problem, you need to break down the inequality into its components and create a scenario that illustrates the inequality. This can be done by identifying the variables, constants, and operations involved in the inequality.

Q: What are some common mistakes to avoid when converting linear inequalities into word problems? A: Some common mistakes to avoid when converting linear inequalities into word problems include:

Not identifying the variables and constants in the inequality
Not creating a realistic scenario that illustrates the inequality
Not using clear and concise language in the word problem
Not providing enough information to solve the problem

Q: How do I create a word problem that illustrates a linear inequality? A: To create a word problem that illustrates a linear inequality, you need to identify the variables, constants, and operations involved in the inequality and create a scenario that illustrates the inequality. This can be done by:

Identifying the variables and constants in the inequality
Creating a scenario that illustrates the inequality
Using clear and concise language in the word problem
Providing enough information to solve the problem

Q: What are some examples of word problems that illustrate linear inequalities? A: Some examples of word problems that illustrate linear inequalities include:

A person has 4 times as many dollars as their friend. If their friend has 6 more dollars than they do, and they have more than 10 dollars, how many dollars do they have?
A company has 4 times as many employees as a nearby company. If the nearby company has 6 more employees than the company, and the company has more than 10 employees, how many employees does the company have?
A bookshelf has 4 times as many books as a nearby bookcase. If the bookcase has 6 more books than the bookshelf, and the bookshelf has more than 10 books, how many books does the bookshelf have?

Q: How do I solve a word problem that illustrates a linear inequality? A: To solve a word problem that illustrates a linear inequality, you need to:

Read the word problem carefully and identify the variables, constants, and operations involved in the inequality
Create an equation or inequality that represents the situation
Solve the equation or inequality to find the solution
Check the solution to make sure it is reasonable and makes sense in the context of the problem

Q: What are some tips for creating effective word problems that illustrate linear inequalities? A: Some tips for creating effective word problems that illustrate linear inequalities include:

Using clear and concise language
Providing enough information to solve the problem
Creating a realistic scenario that illustrates the inequality
Using variables and constants that are relevant to the problem
Making sure the solution is reasonable and makes sense in the context of the problem

Q: How do I know if a word problem is a good example of a linear inequality? A: A word problem is a good example of a linear inequality if it:

Involves a comparison between two values using the greater than or less than symbols
Can be represented by an equation or inequality
Has a solution that is reasonable and makes sense in the context of the problem

Q: What are some common applications of linear inequalities in real-world situations? A: Some common applications of linear inequalities in real-world situations include:

Budgeting and financial planning
Resource allocation and management
Optimization and decision-making
Science and engineering applications
Business and economics applications

Q: How do I use linear inequalities to solve real-world problems? A: To use linear inequalities to solve real-world problems, you need to:

Identify the variables, constants, and operations involved in the problem
Create an equation or inequality that represents the situation
Solve the equation or inequality to find the solution
Check the solution to make sure it is reasonable and makes sense in the context of the problem

Q: What are some common mistakes to avoid when using linear inequalities to solve real-world problems? A: Some common mistakes to avoid when using linear inequalities to solve real-world problems include:

Not identifying the variables and constants in the problem
Not creating a realistic scenario that illustrates the inequality
Not using clear and concise language in the problem
Not providing enough information to solve the problem
Not checking the solution to make sure it is reasonable and makes sense in the context of the problem